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@cuixin
Last active October 30, 2023 06:52
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des ecb mode in golang
package main
import (
"bytes"
"crypto/des"
"errors"
)
func PKCS5Padding(ciphertext []byte, blockSize int) []byte {
padding := blockSize - len(ciphertext)%blockSize
padtext := bytes.Repeat([]byte{byte(padding)}, padding)
return append(ciphertext, padtext...)
}
func PKCS5UnPadding(origData []byte) []byte {
length := len(origData)
unpadding := int(origData[length-1])
return origData[:(length - unpadding)]
}
func ZeroPadding(ciphertext []byte, blockSize int) []byte {
padding := blockSize - len(ciphertext)%blockSize
padtext := bytes.Repeat([]byte{0}, padding)
return append(ciphertext, padtext...)
}
func ZeroUnPadding(origData []byte) []byte {
return bytes.TrimFunc(origData,
func(r rune) bool {
return r == rune(0)
})
}
func DesEncrypt(src, key []byte) ([]byte, error) {
block, err := des.NewCipher(key)
if err != nil {
return nil, err
}
bs := block.BlockSize()
src = ZeroPadding(src, bs)
// src = PKCS5Padding(src, bs)
if len(src)%bs != 0 {
return nil, errors.New("Need a multiple of the blocksize")
}
out := make([]byte, len(src))
dst := out
for len(src) > 0 {
block.Encrypt(dst, src[:bs])
src = src[bs:]
dst = dst[bs:]
}
return out, nil
}
func DesDecrypt(src, key []byte) ([]byte, error) {
block, err := des.NewCipher(key)
if err != nil {
return nil, err
}
out := make([]byte, len(src))
dst := out
bs := block.BlockSize()
if len(src)%bs != 0 {
return nil, errors.New("crypto/cipher: input not full blocks")
}
for len(src) > 0 {
block.Decrypt(dst, src[:bs])
src = src[bs:]
dst = dst[bs:]
}
out = ZeroUnPadding(out)
// out = PKCS5UnPadding(out)
return out, nil
}
package main
import (
"fmt"
"testing"
)
func TestDesEncrypt(t *testing.T) {
key := []byte("5e8487e6")
origtext := []byte("hello world123563332")
erytext, err := DesEncrypt(origtext, key)
if err != nil {
t.Fatal(err)
}
fmt.Printf("%v\n", erytext)
destext, err2 := DesDecrypt(erytext, key)
if err2 != nil {
t.Fatal(err2)
}
fmt.Println(string(destext))
fmt.Println(len(origtext), len(string(destext)))
fmt.Println(string(origtext) == string(destext))
}
go test . -v
@PseudoCowboy
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您好,我最近在做des加解密,搜到您的代码。
想问两个问题:
1.用0补位那个方法有什么好处吗?
2.我要加密一个整形,用这种方法有没有什么问题?
能否帮忙解答一下

@dockercore
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@很明显节省内存开销呀 😄

@rsmnarts
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Hi sir, how about when my secret key length is 32 bytes @cuixin ?

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